Process of reacting cellulosic fibers with sultones and optionally with other creaseproofing agents and resulting products



United States Patent Office 3,506,390 Patented Apr. 14, 1970 Int. (:1. D06m 9/00 us. (:1. 8115.7 15 Claims This invention relates to the treatment of fibrous materials. More particularly, the invention relates to a process for treating cellulosic fibrous materials to improve their reactivity, to resulting products and to the use of the said products.

Specifically, the invention provides a new and improved process for treating cellulosic fibrous material, and particularly cellulosic textile products, to lmprove the reactivity to cross-linking agents and the like. This process comprises impregnating the desired fibrous materials with an aqueous caustic solution, and then treating the resulting impregnated fabric with an aqueous medium containing a sultone, and preferably a hydrocarbon sultone as propane sultone. The invention further provides the new and improved fibrous materials produced by this technique.

As a special embodiment the invention provides a technique for utilizing the above-described new cellulosic fibrous materials in preparing materials having improved crease and shrink resistance which comprises treating the above-described new cellulosic fibrous materials treated with the sultone to an aqueous medium containing a cellulosic treating agent such as, for example, polyepoxide-formaldehyde, acrolein-formaldehyde resins, urea-formaldehyde resin, and the like.

It is known that many textile fabrics, such as cotton, have poor resilience, i.e., they are easily creased or wrinkled when crushed or otherwise subjected to localized physical pressure. In addition, many of these fabrics have poor dimensional stability as exemplified by poor resistance to shrinkage. In order to overcome these short comings, it as been common practice to treat the fabric with a resin such as an ureaor melamine-formaldehyde resin. While this method has met with some success, it has been found that the substantivity of the cross-linking agent to the fabric is in most cases non-existent and that strong catalysts and considerable cross-linking agent is needed in the reaction even to obtain a small degree of reactivity with the fabrics. In addition, the pad baths containing the urea resins have limited stability and must be used in a relatively short period of time. It is, therefore, highly desirable to develop some type of technique which would permit a higher degree of reactivity of the cellulosic fibers with the cross-linking agents using a bath of unlimited stability.

It is an object of the invention, therefore to provide a new method for treating textile materials. It is a further object to provide a method for treating fibrous materials to improve their reactivity toward cross-linking agents and other reactants. It is a further object to provide a method for modifying fibrous materials so that they will have improved reactivity to formaldehyde and to urea-formaldehyde, melamine-formaldehyde and acrolein-formaldehyde resins. It is a further object to provide a method for preparing cellulosic fabrics which have active acidic sites. It is a further object to provide a method for reaction of cellulosic materials with reactants which normally require an acid catalyst without the use of acidic catalysts. It is a further object to provide a process which utilizes a bath of unlimited stability. It is a further object to provide a method for treating textiles to improve their dyeability. It is a further object to provide a process for improving the hydrophilic properties of cellulosic fabrics. It is a further object to provide fibrous materials having improved wet and dry crease recovery. It is a further object to provide a method of modifying textile materials so that they might have increased stiffness. Other objects and advantages of the invention will be apparent from the following detailed description thereof.

It has now been discovered that these and other objects may be accomplished by the process of the invention which comprises impregnating the desired fibrous material with an aqueous caustic' solution and then treating the resulting impregnated material with an aqueous solution containing a sultone, and preferably propane sultone. It has been found that by this special technique that the cellulosic fibrous material may be modified so as to have greatly increased reactivity toward materials such as cross-linking agents, basic dyes and the like. It has been found, for example, that textile fabrics which have been treated according to this process are highly reactive toward agents such as formaldehyde, urea-formaldehyde resins, dimethylol ethylene urea, acroleinformaldehyde resins and melamine-formaldehyde resins, and rapidly react therewith to form materials having very high wet and dry crease recovery. It has been further found that the modified cellulosic material reacts with the cross-linking agents and other reactants without the use of conventional acidic catalysts. In addition, materials react readily with basic dyes which give colors which are deeper and more resistant to fading by light and washing. Further advantage is also found in the fact that the fibrous materials treated according to the process have greater stiffness and can be utilized as such for many important applications in the textile industry. Further, the new modified cellulosic products have residual strong acidity which permits further reaction or modification.

The sultones used in the process of the invention are intermolecular cyclic esters of hydroxysulfonic acids and may be derived both from aliphatic, cycloaliphatic and aromatic acids. Examples of sultones suitable for the present process include 1,3-propane sultones, 1,4-butanesultones, 1,3-hexanesultones, benzylsultones, tolylsultone, and mixtures thereof. The present sultones to-be employed are the gamma sultones and preferablythe hydrocarbon sultones as 1,3-propane sultone. The sultones may be prepared by conventional techniques such as sulfochlorination of chlorinated hydrocarbons and subsequently using the resulting chlorosulfonic acid in the formation of the sultones. I

According to the process of the invention, the fibrous material to be treated is brought into contact. with an aqueous caustic solution. The caustic employed is preferably sodium hydroxide but potassium hydroxide or other alkali or alkali earth metal hydroxides may be utilized. The strength of the caustic solution may vary but preferred concentrations vary from about 1% to 30% by weight. Standard mecerizing procedures generally utilize concentrations of about 16-18% caustic and such solutions are ideally suited for the present process. In fact, the present process can follow the mercerizing step directly and thus fit into normal textile Wet processing mill practices. Overall preferred concentrations generally range from about 5.0% to 20% by weight.

The impregnation with the aqueous caustic may be accomplished by any suitable means, such as, for example, by dipping, spraying, padding and the like. It is generally preferred to pass the fibrous material into and through the aqueous solution as by padding. The amount of Wet pick-up will vary with the different cases, but generally 3 it is preferred to have a wet-pick-up varying from about 20% to 100%.

The temperature of the cautic solution as well as the temperature of the fibrous material to be impregnated may vary, but in general, it is preferred to have both at about ambient temperature. Mercerizing temperatures of about 50 F. to 100 F. are generally preferred.

The material impregnated with the caustic material is then treated with an aqueous solution of the sultone. The solution of the sultone may be prepared in any manner such as mixing the sultone with water, acetone, alcohol and the like or mixtures thereof. It is generally preferred to employ an aqueous solution. Concentration of the sultone solution may vary over a wide range. It is generally preferred to employ solutions varying from about 1% to 25% by weight.

It is also desirable in some cases to employ wetting agents. These agents may be any of the known cationic, anionic or non-ionic materials and may have a great variety of different compositions. Preferred materials include the ionic agents and especially those having a polar structure including a hydrophilic (predominantly hydrocarbon) residue and a charged ionic radical thereon; such anionic surface active compounds include alkali metal and nitrogen-base soaps of higher fatty acids, such as potassium, and sodium myristate, laurate, palmitate, oleate, stearate, ammonium stearate, etc., as well as salts of long-chain aliphatic amines and quaternary ammonium bases, such as lauryl amine hydrochloride, stearyl amine hydrochloride, and the like. Examples of the nonionic agents include the partial esters of polyhydric alcohols and fatty acids, such as the hexitans and hexitide esters as sorbitan monolaurate, hydroxypolyoxyalkylene ethers of the above-described partial esters as the polyethylene glycol ethers of sorbitan monolaurate, the hydroxypolyoxyalkylene ethers of phenols as the reaction product of ethylene oxide and bis-phenol-A and the like and mixtures thereof. These materials are preferably employed in amounts varying from about .l% to 5% by weight, and still more preferably f .om 0.5% to 3% by weight.

The impregnation of the caustic treated fibrous material may be accomplished by any suitable means such as, for example, by dipping, spraying, padding and the like. It is generally preferred to pass the fibrous material into and through the sultone solution as by padding. The amount of wet pick-up Will vary with the different situations but generally is preferred to have a wet pick-up varying from to 100%.

The temperature of the sultone solution as Well as the temperature of the caustic treated fibrous material to be impregnated may vary over a wide range. In general, the temperature may vary from about C. to 90 C. and more preferably between C. and 70 C.

The length of time required for the reaction with the sultone may vary depending upon the temperature and concentration of solution. In most cases, at elevated temperatures the reaction can be completed within one or tWO hours.

After the impregnated material is removed from contact with the sultone solution it may then be washed to remove any excess reactants, dried and then used imme diately in the intended commercial applications. Washing is preferably accomplished by use of water or water containing detergents and then drying at temperatures ranging from ambient temperature to 125 C.

The material obtained by the above-described process will have the same appearance as before but will generally have a stilt feel and can be used as stiffening materials in a variety of different textile materials. The new material will also be characterized by having greater elongation. The material will have substantially the same strength and non-chlorine retaining properties as before the treatment.

The fibrous material prepared by the process of the invention will have many active sufonic acid sites and as noted above are highly reactive toward many cross-linking agents and materials. Examples of such materials include formaldehyde and resinous precondensates such as acrolein-formaldehyde, acrolein-urea-formaldehyde, formaldehyde reaction products with ethylene urea, melamine, and dicyandiamide. Other examples include the ketone aldehyde reaction products, poly epoxides, and the like. In the application of these materials to these impregnated fibrous materials any of the conventional techniques may be employed. The preferred techniques are generally to prepare an aqueous padding solution containing these agents and any desired additives such as softening agents and then pass the impregnated fibrous material into and through the solutions removing the excess solutions and curing the treated fabric. Concentrations of padding solutions generally vary from about 5% to about 25% with preferred concentrations ranging from 5% to 15%. Temperatures employed in the treatment will generally vary from about 20 C. to about C. Temperatures employed in the curing step will generally vary from 70 C. to C.

The products treated as above may then be utilized for any of the intended applications. The textile materials, for example, may be used in the manufacture of dresses, drapes, upholsteries, shoe fabrics, carpets, coats, shirts, uniforms, shoes, cords, construction fabrics and the like.

The above-described process may be utilized for the treatment of any cellulosic fibrous material. This includes paper, wood and textile materials. The textile materials may be woven and non-woven fabrics, threads, gauze, yarn, cord, string, netting and the like. The process also includes treatment of materials which have been pretreated, e.g., mercerized. By cellulosic is meant material which has any part, and preferably at least 40%, derived from cellulosic materials, such as natural cellulose such as cotton, linen, and the like, and other cellulosics such as viscose rayon, cuprammonium rayon, regenerated cellulose, cellulosic acetate, as well as mixtures with wool, synthetics as fibers derived from acrylonitrile (Orlon- 100% acrylonitrile polymer), vinylidene cyanide polymers, polyamides (nylon-super polyamides), polyesterpolyamides, polymers prepared from corn protein and formaldehyde, as well as copolymers of the above monomers as, for example, Aerilan (85% acrylonitrile and 15% vinyl acetate), Dynel (60% vinyl chloride and 40% acrylonitrile), Saran (85 vinylidene chloride and 15 vinyl chloride), and other synthetic fabrics or fibers prepared from polyalkylenes as polyethylene, polypropylene, polyurethanes, mineral fibers (Fiberglas), and alginic materials as alginate rayon.

The preferred materials to be employed in the process include those textile materials containing at least 30% cellulosic materials and preferably those derived from cotton and rayon, and cellulose acetates.

To illustrate the manner in which the invention may be carried out, the following examples are given. It is to be understood, however, that the examples are for the purpose of illustration and the invention is not to be regarded as limited to any of the specific materials or conditions recited therein.

The wrinkle recovery values (MCRA) reported in the examples were determined by the Tentative Method of Test for Recovery of Textile Fabrics From Creasing, Using the Vertical Strip Apparatus, ASTM desig. D1295-53T (as reported as sum of average warp and fill measurements), and the tensile strength values were determined by Federal Specifications CCCT191.6, Instron Tensile Testing Machine, Method 5100. All tests were carried out at 65i2% relative humidity 20 and EXAMPLE I This example illustrates the treatment of cotton fabrics with a solution containing propane sultones.

Cotton fabric 3.1 oz./sq. yard (80 x 80 count) was allowed to soak in a 20% sodium hydroxide solution for 15 minutes at room temperature. The fabric was then removed and the excess solution removed by squeezing through rubber coated squeeze rolls. The wet fabric was then placed in an impregnating solution made up of 25 grams of propane sultone, 75 grams of water and 3 grams sodium myristyl sulfate. The fabric was allowed to re main in this solution, for one-half hour at 120 F. It was then removed, the excess solution removed by squeezing through a squeeze roll and the fabric was then washed thoroughly and then dried 12 minutes at 250 F. The treated fabric which contained 0.49% sulfur as sulfonic acid was then passed into and through a solution containing of an acrolein-formaldehyde condensate which had been prepared by the method described in U.S. Patent 3,080,281. The treated fabric was cured by heating for 5-10 minutes at 325 F. The dried fabric was then examined to determine the crease resistance and the tensile strength. The results are shown in the following table:

Strip MCRA tensile,

lbs., warp/ Textile Wet Dry filling Untreated fabric 140 133 60/33 Fabric treated with propane sultone. 166 145 64/43 Propane sultone treated fabric plus acrolein-Ionnaldehyde resin 272 242 19/10 Untreated fabric plus acroleinformaldehyde without any added catalyst EXAMPLE II Example I was repeated with the exception that the resin used to treat the propane sultone treated fabric was dimethylol ethylene urea. The results are shown in the table below:

1 Strip MC RA tensile,

lbs., Warp/ Textile Wet Dry filling Untreated fabric 140 133 60/33 Propane sultone treated fabric treated with dimethylol ethylene urea 282 194 24/14 Untreated fabric plus dimethylol ethyl- Unchanged over untreated ene urea without acid catalyst fabric EXAMPLE III Example I was repeated with the exception that the conditions for the caustic treatment, the amount of the propane sultone and conditions for cure were modified as shown in the table below. The amount of sulfur was determined in each case to demonstrate the degree of reaction with the cellulose. The results are as indicated:

1st Step NaOH 2nd step Propane Sultone Sulfur,

percent w.

Percent Min./ F. Percent Min./ F. on fabric Untreated 01 fabric.

1 Treated fabric washed thoroughly to remove unreaeted materials.

6 EXAMPLE IV This experiment demonstrates the improved dye receptivity 30 obtained with the modified products of the present invention.

Cotton fabric was treated with 20% NaOH for 15 minutes at 75 F. and then with 10% propane sultone for 60 minutes at F. according to the technique set out in Example I. 3 x 3 inch swatches were then dyed by treating with 0.1% methylene blue and 0.1% acetic acid and boiling for /2 hour. The percent reflectance was determined and shown below in comparison to that of the untreated fabric and fabric treated only with the caustic.

Percent Fabric Color Reflectance Untreated Royal blue 44 Fagrigltireated only with 20% Darker blue than above 43 Fabric treated with 20% NaOH Very dark blue 1. 5

and 10% propane sultone as noted above.

EXAMPLE V An additional series of experiments were done to show the improved dye receptivity of the new products using a less concentrated dye bath and different amounts of propane sultone. The swatches were boiled 30 minutes in 0.01% methylene blue and 01% acetic acid. The results are indicated in the table below:

concentration of the sodium hydroxide was 17.6%, the concentration of the propane sultone was 10% and the propane sultone treating bath was 160 F. The resulting fabric was treated with a 10% aqueous solution of glycidyl ether of glycerol and cured at C. The resulting fabric had good crease resistance.

EXAMPLE VIII Example I was repeated with the exception that the cotton fabric was replaced by a fabric made up of 35% cotton and 65% Dacron polyethylene terephthalate. Related results are obtained.

I claim as my invention:

1. A process for improving the properties of cellulosic fibers which comprises impregnating cellulosic fibers with an aqueous caustic solution and then treating the resulting fibers with a hydrocarbon sultone or mixtures of hydrocarbon sultones selected from the group consisting of lower alkyl hydrocarbon sultones, benzyl sultone, tolyl sultone and mixtures thereof in an inert solvent solution and reacting said fibers with said sultones while said fibers are wet with said caustic and sultone solutions.

2. A process for preparing crease resistant textile fabrics which comprises treating cellulosic fibers in textile fabric form by the process of claim 1 and then treating the fabrics resulting from said process by creaseproofing said fabrics with a cellulosic, cross-linking creaseproofing agent, other than said sultones, in the absence of added catalyst for said creaseproofing agent.

3. A process for improving the properties of cotton containing fabrics which comprises impregnating said fabrics with an aqueous sodium hydroxide solution which swells the cotton fibers in said fabrics and then treating the resulting fabrics with a hydrocarbon sultone or mixtures of hydrocarbon sultones selected from the group consisting of lower alkyl hydrocarbon sultones, benzyl sultone, tolyl sultone and mixtures thereof in an inert solvent solution and reacting said fibers with said sultones while said fibers are wet with said caustic an sultone solutions.

4. A process for improving the properties of a cotton fabric as defined in claim 3 wherein the concentration of the sodium hydroxide solution varies from 5% to 25% by weight.

5. A process as in claim 3 wherein the hydrocarbon sultone is propane sultone.

6. A process as in claim 3 wherein the impregnation is accomplished at a temperature between 20 C. and 100 C.

7. A process as in claim 3 wherein the fabric is made up substantially of cotton.

8. A process as in claim 3 wherein the fabric is a mixture of cotton and polyethylene terephthalate.

9. A process for preparing cotton containing textile fabrics resistant to creasing in the wet or dry state which comprises treating the fabrics resulting from the process of claim 3 by creaseproofing said fabrics with a resinous condensate, cellulosic, cross-linking creaseproofing agent, other than said sultones, in the absence of added catalyst for said creaseproofing agent.

10. A process for preparing crease resistant cotton textile fabrics which comprises impregnating said fabrics with an aqueous caustic solution and then treating the resulting fabrics with an aqueous solution of propane sultone and reacting said fabrics with said sultone while said fabrics are wet with said caustic and sultone solutions, and subsequently creaseproofing said fabrics with an aqueous solution of an acroleinformaldehyde condensate creaseproofing agent in the absence of added catalyst for said creaseproofing agent.

11. A process for preparing crease resistant fabrics containing cellulosic fibers which comprises impregnating said fabrics with an aqueous sodium hydroxide solution and then treating the resulting fabrics with an aqueous solution of propane sultone and reacting said fabrics with said sultone while said fabrics are wet with said caustic and sultone solutions, and subsequently creaseproofing said fabrics with an aqueous solution of a creaseproofing agent selected from the group consisting of formaldehyde, urea-formaldehyde resins, melamine-formaldehyde resins, dicyandiamide-formaldehyde resins, acrolein-formaldehyde resins, ketone-formaldehyde resins and polyepoxides in the absence of added catalyst for said creaseproofing agent.

12. A process of improving the properties of cellulosic fibers which comprises impregnating cellulosic fibers with a lower alkyl hydrocarbon sultone and with an aqueous caustic solution and reacting said fibers with said sultone while said fibers are impregnated with said caustic solution.

13. The improved cellulosic fibers produced by the process of claim 1, said improved cellulosic fibers produced by said process being more acidic, more hydrophilic and more basic dye receptive than the untreated cellulosic fibers from which they were produced.

14. The improved cotton fabric produced by the process of claim 1 when the cellulosic fibers are in cotton fabric form, said improved cotton fabric produced by said process being more acidic, more hydrophilic and more basic dye receptive than the untreated cotton fabric from which it was produced.

15. The improved cotton fabric produced by the process of claim 5, said cotton fabric produced by said process being more acidic, more hydrophilic and more basic dye receptive than the untreated cotton fabric from which it was produced.

References Cited UNITED STATES PATENTS 2,989,364 6/1961 Goldann 8-1155 FOREIGN PATENTS 570,888 3/1959 Belgium. 1,146,870 4/ 1963 Germany.

DONALD LEVY, Primary Examiner US. Cl. X.R. 

1. A PROCESS FOR IMPROVING THE PROPERTIES OF CELLULOSIC FIBERS WHICH COMPRISES IMPREGNATING CELLULOSIC FIBERS WITH AN AQUEOUS CAUSTIC SOLUTION AND THEN TREATING THE RESULTING FIBERS WITH A HYDROCARBON SULTONE OR MIXTURES OF HYDROCARBON SULTONES SELECTED FROM THE GROUP CONSISTING OF LOWER ALKYL HYDROCARBON SULTONES, BENZYL SULTONE, TOLYL SULTONE AND MIXTURES THEREOF IN AN INERT SOLVENT SOLUTION AND REACTING SAID FIBERS WITH SAID SULTONES WHILE SAID FIBERS ARE WET WITH SAID CAUSTIC AND SULTONE SOLUTIONS. 